The present invention relates to the field of orthopedic surgery and in particular spinal surgery.
The invention more particularly relates to bone anchoring instrumentations, for implanting at least one anchoring device in at least one bone tissue, optionally associated with at least one implant, in particular a spinal implant (such as intervertebral prostheses and intersomatic cages).
A problem in this field relates to the reliability and stability of anchoring devices inside bone tissues, whether these anchoring devices are either associated with one or several implants or not. In particular, the anchoring devices should preferably cause minimum lesions to the bone tissue (avoid cracks and more significant damages than is required by the size of the actual device), but they should especially allow reliable fixation since many therapeutic techniques rely on bone growth which generally requires that the devices anchored in the bone tissue remain as immobile as possible. Further, another problem relates to the facility of implantation. Indeed, there exists a risk that the anchoring device be poorly positioned, especially because of the difficulty in technically carrying out the implantation of the anchoring device. Thus, it is for example possible that a too external (or even internal) position of the anchoring device with respect to the bone tissue, have detrimental consequences, such as for example the weakening of its stabilizing capability.
Patent applications published as WO 2008/149223, WO 2011/80535 and FR 2 987 256 filed by the applicant of the present application are known in the prior art, entirely incorporated herein by reference and to which the reader may refer for examining the various solved problems and the advantages provided by this type of solutions, including a bone anchoring instrumentation, particularly for the fixation, between vertebrae, of implants such as intervertebral disc prostheses or intersomatic cages. In the particular case of the rachis, various types of vertebral implants are known such as intervertebral disc prostheses or intersomatic cages or of corpectomy for example, or further vertebral plates or interspinal implants. These various types of implants generally have to be as less invasive as possible in order to facilitate their implantation and limit the risks of damages to the sensitive surrounding tissues which are notably nerves and blood vessels. The same applies for the bone anchoring devices (such as the straight or curved anchors or further screws) since it is preferable that the fixation occupies as less space as possible while being as reliable as possible.
However, these solutions are very specific to the implants for which they are intended to allow fixation and cannot be used or adapted for other types of orthopedic surgery (i.e., other implants and other bone tissues than those of the rachis). Further, the reliability of the bone anchoring may still be improved, especially in order to allow the fixation of other types of implants (for example smaller implants) for which the bone anchoring has to be more stable. Indeed, depending on the type of implant which is to be placed and/or depending on the type of bone on which the implant is desirably anchored, it may be desirable to have an extended anchoring and/or variable depth, especially a more “expansed” or “deployed” anchoring, i.e. greater than allowed by these known solutions. Thus, it is generally intended that the anchoring devices may be rapidly or easily implanted with minimum invasivity, i.e. one seeks to limit the size of the incisions and of the damages on the surrounding tissues. Indeed, access to the implantation sites (such as the intervertebral spaces) is often delicate because of the congestion, especially near the intervertebral space because of the presence of blood vessels and nerves. It will be noted that the invasivity problem provides additional constraints for addressing the problem of stability, especially because the fact of reducing the dimensions for reducing the invasivity is accompanied by risks of unstability. It is therefore interesting to provide a solution which gives the possibility of reconciling the constraints related to invasivity and stability, i.e. limiting the invasivity (reduced as compared with known solutions) while providing a performing anchoring, or even as more performing, in the bone tissue.
In this context, it is interesting to propose a bone anchoring, notably through implants and/or anchoring devices and/or instrumentation, which may be easy, stable, reliable and as less invasive as possible.